The problem of disposing of solid waste has been increasing for many years with the growth of population and is now critical in the larger cities. The usual manner of disposing of solid waste has been to use it for land fill, to dump it into water, or to incinerate it. Suitable land fills areas are becoming increasingly hard to find. Dumping solid wastes into water presents pollution problems, Incinerating solid wastes pollutes the air with harmful gases and increases its CO.sub.2 content. When rains remove excess CO.sub.2 content from the air, the acidity of rain water is increased and this may have harmful effects on plants, animal life and buildings. Incinerators require tall stacks and scrubbers to remove harmful components from the gas and these structures are quite expensive.
Numerous efforts have been made to solve solid waste problems but none have been entirely satisfactory. One proposal subjects solid wastes to dry distillation or pyrolysis at temperatures between about 900.degree.C. and about 1200.degree.C. without the injection of steam or oxygen and thereby produces crude oil. Scrubbing the gas products of this process is required and the scrubbing treatment causes pollution of water and atmosphere.
Another proposal includes the steps of applying heat externally to a retort in which garbage is heated without internal combustion. The garbage is distilled or pyrolized at a temperature of about 400.degree.C. The resulting gas is cracked, enriched, and scrubbed to make it suitable for heating and illuminating purposes. The scrubbing of the gas creates pollution problems.
Another proposal calls for garbage to be destructively distilled while on a traveling grate in an open system. Organic material is thermally decomposed at temperatures between about 1000.degree.F. and about 2000.degree.F. in the absence of oxygen. Some 34-36% of the starting material remains at the completion of the process. Most of the gas produced during the process is consumed in the process and the gas which is not so consumed is heavily diluted with carbon dioxide and nitrogen and is not suitable for uses in the chemical industry.
In other proposals complete combustion processes are used but without the recovery of any useful ingredients from the resulting gas. As a result of these processes the atmosphere is polluted by the gas, and the CO.sub.2 content of the atmosphere is increased.
Still other proposals have as their objective the removal and upgrading of oil in oil shale. Such proposals produce hydrogen by using steam by partially burning oil in the presence of a catalyst.